Reland: Add a trace-event for each runtime-stats timer (CL 2052523002)

src/tracing/trace-event.h

Index: src/tracing/trace-event.h
diff --git a/src/tracing/trace-event.h b/src/tracing/trace-event.h
index 2b3bf9bf92cca8fc5524ee1e644057d43795a0f1..48454705d56d7ad7eba379165a5b6f6e915203ae 100644
--- a/src/tracing/trace-event.h
+++ b/src/tracing/trace-event.h
@@ -133,6 +133,7 @@ enum CategoryGroupEnabledFlags {
       ->UpdateTraceEventDuration
 
 // Defines atomic operations used internally by the tracing system.
+#define TRACE_EVENT_API_ATOMIC_BYTE v8::base::Atomic8
 #define TRACE_EVENT_API_ATOMIC_WORD v8::base::AtomicWord
 #define TRACE_EVENT_API_ATOMIC_LOAD(var) v8::base::NoBarrier_Load(&(var))
 #define TRACE_EVENT_API_ATOMIC_STORE(var, value) \
@@ -594,4 +595,31 @@ class TraceEventSamplingStateScope {
 }  // namespace internal
 }  // namespace v8
 
+// V8 Specific macros
+
+// Runtime calls happen at a high frequency, the following set of macros
+// minimizes the tracing overhead of those calls. A global variable is set
+// when top level V8 API is called, and checked per runtime call.
+extern TRACE_EVENT_API_ATOMIC_BYTE g_runtime_calls_trace_enabled;
+
+#define TRACE_IS_RUNTIME_CALLS_TRACING_ENABLED() \
+  TRACE_EVENT_API_ATOMIC_LOAD(g_runtime_calls_trace_enabled)
+
+#define TRACE_CHECK_AND_SET_RUNTIME_CALLS_TRACING()                            \
+  do {                                                                         \
+    INTERNAL_TRACE_EVENT_GET_CATEGORY_INFO(                                    \
+        TRACE_DISABLED_BY_DEFAULT("v8.runtime"));                              \
+    TRACE_EVENT_API_ATOMIC_STORE(g_runtime_calls_trace_enabled,                \
+        INTERNAL_TRACE_EVENT_CATEGORY_GROUP_ENABLED_FOR_RECORDING_MODE() ? 1   \
+                                                                         : 0); \
+  } while (0)
+
+#define TRACE_RUNTIME_CALL(name)                                               \
+  do {                                                                         \
+    if (V8_UNLIKELY(TRACE_IS_RUNTIME_CALLS_TRACING_ENABLED())) {               \
+      INTERNAL_TRACE_EVENT_ADD_SCOPED(TRACE_DISABLED_BY_DEFAULT("v8.runtime"), \
+                                      name);                                   \
+    }                                                                          \
+  } while (0)
+
 #endif  // SRC_TRACING_TRACE_EVENT_H_